Cutout construction



Jan. 11, 1944. w. o. scHULTz r AL 2,338,823

CUT-OUT CONSTRUCTION Filed July 8, 1936 asheets-sheet 2.

` INVENTORS 17 Mum/1 O. 5cm/UZ BY Auw/v 6. 57E/Mmm? Qzz; /f v v A ORNEY.

. Jan. 11, 1944.. w. o. SCHUL-rz ETAL CUT-OUT CONSTRUCTION 3Sheets-Sheet 3 Filed July 8, 1936 ww A i Patented Jan. 11, 1944 CUroU'rCONSTRUCTION William 0. Schultz, South Milwaukee, and Alwin G.Steinmayer, Milwaukee, Wis., assignors to Line Material Company, SouthMilwaukee, Wis., a corporation of Delaware Application July 8, 1936,Serial No. 89,552 22 claims. (ol. zoo- 114) This invention relates to acut-out construc- Ation and is particularly directed to a fuse type ofcut-out. Fuse types of cut-outs are frequently mounted in exposedpositions on poles, for instance, where they are subjected to severeweather conditions and frequently ice and sleet form on the housings.Objects of this invention are to provide a novel form of cut-out inwhich a housing is provided with a door adapted to drop open after thefuse blows, in which a movably mounted fusetube is carried within thehousingv and is adapted to drop downwardly after the fuse blows, inwhich a fuse link is carried within the tube and is adapted to besevered upon overload, the construction being such that when the fuselink blows, the circuit through the device is interrupted and when thefuse tube slides downwardly, at least one of the contacts of the fusetube is thereby mechanically spaced a distance from the stationarycontact of the housing, thus providing additional separation or break inthe circuit, and in which when the fuse door drops open, the contact ofthe fuse tube and its associated parts are bodily carried a considerabledistance away from the stationary contacts of the housing, the devicethereby providing means which will insure interruption of the circuitupon overload under all conditions of operation and one in whichnormally all three of the above listed functions occur.

In other words, objects of this invention are to provide a fuse type ofcut-out in which the normal interruption of the circuit by the severingof the fuse link is obtained. Additionally sepa ration of at least oneof the contacts of the fuse tube and its associated structure from thecorresponding stationary` contact of the housing is obtained whether thedoor freezes closed or not, and in which under normal operationsadditional protection is afforded by the outward dropping of the door sothat the contact of the fuse tube and its associated structure are movedoutwardly from the stationary contacts of the housing, thereby providingwhat may be called triple safety of operation and insuring adequateoperation under even the most adverse conditions.

Further objects are to provide a fuse construction in which the downwardthrust of the fuse tube is not borne directly by the fuse link but isborne by a releasing mechanism which also serves as a fuse linkextractor to quickly remove any remaining portions of the link after thefuse has blown, in which the upward thrust of the fuse tube and doorassembly is borne by rigid members and transmitted to the housing, in

which means are provided for prevent AAgathe door from being blown openin the eventfthatgas pressure is suddenly generated within thefliouslngby latch means which also constitutes jmeans for providing an adequatecontact engagement between the contact at the closed end of the fusetube and the stationary contact of the` housing, in which this contactmeans assists in the downward motion of the fuse tube when the fuse'tube is released, and to provide additional latch means to more denitelyinsureagainst the door vibrating open if the device is located in a`position where it is subject to vibrations.

Further objects are to provide a construction in which one of thecontacts, for example the lower contact, always pushes outwardly toassist in opening the door when the fuse tube is released, in which asimple type of contact construction is employed, and in which the doormay 4be opened or closed without straining the fuse link while the fuselink is intact.

Further objects are to provide a novel method of attaching the retainingpin to the lower ferrule of the fuse tube and 'for locking `the pin andthe lower ferrule or sleeve of the fuse tube'to the fuse tube, and inwhich a novel construction of combined thumb nut and washer is providedfor locking the outer end of the fuse link in place vithout danger ofcutting or tearing the fuse ink.

Embodiments of lthe inventionl are shown in the accompanying drawings,in which:

Figure l is a sectional elevation through the device. y

Figure 2 is a sectional View on the line 2-2 of Figure l.

Figure 3 is a sectional view on the line 3-3 of Figure 1.

Figure 4 is a view corresponding to Figure l showing a modified form ofconstruction.

Figure 5 is a fragmentary detail showing the manner in which theretaining pin is attached.

Figure 6 is a sectional view on the line 6 6 of Figure 5.

Figure 'l is an enlarged sectional View through the combined thumb nutand washer for securing the free end of the fuse link.

Figure 8 is a face view of the structure shown in Figure 7, with partsbroken away.

Figure 9 is a fragmentary view of the notched projecting lug of the dooragainst which the upper end of the fuse tube bears.

Referring to the drawings, it will be seen that a casing I and a door 2have been provided and formed of insulating material, the casing usuallybeing formed of porcelain or similar material and the door of phenoliccondensation product or other suitable insulatingV material. The door ishinged adjacent its lower ends by means of trunnions 3 carried therebywhich engage in hook like members l carried by the casing and out of anyelectrical connection whatsoever with the contacts of the device.

The casing is provided with an upper terminal member 5 and a lowerterminal member 6 and mayhave an intermediate barrier 1 in accordancewith the usual practice.

The upper terminal member 5 has a pair of spaced arms 8 projectingtherefrom between which is pivotally mounted the upper contact member 9which may be in the form of a lever with a rounded lower face adapted toengage the upper cap or contact I0 of the fuse tube Il, the contactmember 9 being urged into intimate engagement with the contact I0 bymeans of a spring I2. It may be of bell crank shape and one of the arms|3 thereof is adapted to engage a stop I4 when the fuse tube is removedto arrest counterclockwise rotation of the contact member 9 after it hasmoved to a predetermined distance.

This arm |3 may also carry a looped spring I5 provided with a rounded oreye portion i6 engaging over the endof the upper contact I0 of the fusetube and tending to assist in locking the fuse tube against outwardrocking motion, the spring, however, yielding when the door is pulledopen, as will appear hereinafter, as the fuse tube is carried by thedoor.

The door may be provided with an inwardly projecting lug l1 which isnotched, as may be seen from Figure 9, to form a rest for the upper end,for example the contact l0 of the fuse tube structure.

Sometimes the devices are positioned in places where they are subject toconsiderable vibration and to prevent the door from vibrating, orjarring open, a pair of spr-ing arms I8 are provided and equipped withcur/ed ends I9 which fit aroundthe upper contact I0 of the fuse tube.However, the door may be pulled open or pushed closed as these springarms yield. I

The door is provided adjacent its lower end with a metal guide member 20which is securely attached to the door and through which the fuse tubeii may slide. I t is preferable to equip the fuse tube with a metalsleeve or ferrule 2i rigid with the fuse .tube which slides throughv theguide member 20 and it is also preferable to bevel the ends of thisferrule 2|. ber 2li is provided with a rigid bevelled ear or lug 22which fits beneath an upwardly bent stop 23 r1? gidly carried by thelower terminal member ii, to thus limit any recoil of the fuse tube anddoor assembly.

The lower terminal member i3 is provided with a pair of spring arms orcontacts 2t which, as may be seen from Figure 3, are provided withoutwardly turned ends 23 which form a .butt or wedge contact with theguiding member 2li. The fuse tube is provided with an expulsibleconductor which is current responsive andr expelled upon overload. Thismay take the form of a fuse link which may consist of a reduced fusibleportion 26 provided with a button head clamped by the upper contact orcap lil and with a leader 21 which extends downwardly through the openlower end of the fuse tube, the fuse tube being of the expulsion type,and through a notch 28 in the lower end of the fuse tube. The free orouter end of the leader is clamped beneath the thumb nut 29 carried bythe contact or guide member 20.

The thumb nut is preferably provided with a permanently attached,swivelly mounted washer 30, see particularly Figures 7 and 8. Thiswasher is provided with inwardly turned lugs or arms 3| at spaced pointswhich loosely engage over the flange 32 of the thumb nut. Thus it ispossible to tighten the thumb nut without cutting or tearing any portionof the fuse link.

The metal sleeve or ferrule 2| iits over the fuse tube and is lockedthereto by forming a notch in the ierrule and in the fuse tube andpositioning a transverse pin 33 therein, as shown particularly inFigures 5 and 6.

'I'his pin is held in place by forming a pair of slots 34 on oppositesides of the notch in the ferrule 2| to thereby provide a pair of arms35 in the ferrule. These arms are thereafter bent inwardly, as shown inFigure 5, and thus grip the pin 33 and prevent its outward movementradially from the ferrule. The pin 33 is prevented from sliding endwiseby turning its ends inwardly and -locating them within the notch 36 ofthe ferrule 2|. This provides a very simple and ei'- fective way oflocking the ferrule to the fuse tube and at the same time locking thepin to both of these members.

The pin 33 constitutes a stop member, as may be seen from Figure 1, andis positioned below the lower edge of the sleeve 20, thus restrainingthe fuse tube against upward sliding motion under recoil conditions. Thepin is also used to prevent the fuse tube from dropping outwardly byproviding a locking means 31 in the form of a spring U-shaped memberwhose bight portion or bail portion 38 is positioned between the fusetube Il and the leader 21 and is held in place by the leader until thefuse link is ruptured. WhenA the fuse link is ruptured, the lockingmember 31 rocks in a clockwise direction and its upper shoulders aremoved from beneath the pin 33, thus allowing the fuse tube to slidedownwardly.

This latching spring like member also acts in the capacity of a fuselink extractor for when the fuse is severed, it rocks in a clockwisedirection and thus withdraws any remaining unburned portion of the fuselink. Thus if the fuse link has been severed by a small overload notvsufficient to cause a full expulsion action of the fuse tube,nevertheless the fuse link is suddenly pulled from the fuse tube by thefuse link extractor and latching member.

This combined latching member and fuse link extractor may have inwardlyturned end portions 35i which are pivoted in a lug formed on the contactor guide member 20, as shown in Figure l, and the normally horizontallydirected arms may slide upon downwardly bevelled faces or ears lll alsoformed on the guiding member 2t. The upper arms 31 of the springy fuseextractor and locking member tend to approach each other and thus slidealong downwardly bevelled faces i0 and cause the fuse extractor to tendto rock in a clockwise direction, as viewed in Figure 1. Thisconstruction istnore fully described and is claimed in the patent toWilliam O. Schultz No. 2,098,433 of November 9, 1937, for Fuse, and ischosen as one form of locking member that may be employed with thisinvention. If desired ears 40 may be provided and constitute stops tolimit the outward rocking motion of the fuse extractor and latchingmember.

The operationl of the apparatus is as follows: When an overload occurs,the fuse link is ruptured and immediately the member 31 swings in aclockwise direction, thus extracting any unburned portion of the fuselink Also the member 31 when so rocked has moved out of the path oftravel of the pins 33 and the fuse tube II may slide downwardly clear ofthe latching means at the upper.

end of the fuse tube. It slides freely between the arms I 8 as these donot grip the fuse tube and also it slides free of the eye I6 of thespring I5. Additionallyy the upper-contact 9, which is spring presseddownwardly, provides spring pressure for assisting the fuse tube in itsdownward motion. The fuse tube, as soon as it moves` clear of the upperlatching means, releases the fuse door and consequently the fuse doorrocks outwardly and downwardly. The housing is provided with a cut-outor channel like portion 4I which accommodates the projecting end of thefuse tube when the door rocks outwardly and the fuse tube is extended.As a matter of fact, the door rocks outwardly and the fuse tubethereafter slides back downwardly with respect to the then reverseddoor, as the door at the last portion of its stroke hangs verticallydownwardly.

This construction also insures clearing of the fuse tube before themotion of the fuse tube and the subsequent motion of the door occurs.This is due to the fact that recoil holds the fuse tube in its uppermostposition until after the fuse tube has cleared itself and thereafterwhen the recoil force dies out, which occurs in a very brief interval,the fuse tube slides downwardly and the door drops open.

The guiding member may, if desired, be provided with inwardly projectingfeet 42 located on opposite sides of the sleeve or ferrule 2| of thefuse tube.

The slight upward motion that may be permitted the fuse tube upon recoilpresses the lupper contact 9 upwardly a'slight distance and thusincreases the pressure exerted by the eye I6 of the spring Ii againstthe upper contact I0 of the fuse tube to increase the grip of thisportion of the apparatus upon the fuse tube during recoil there? of.This feature, however, is more fully disclosed y and is claimed in thecopending application of William O. Schultz for Cut-outs, Serial No.'70,206 filed March 23, 1936.

It is obvious that the spring I5and the eye I6 may be omitted, as shownin Figure 4. However', the same upper contact S may be employed and maybe spring urged by the spring I2 in identically the same manner as forthe form shown in Figure 1. In both cases the upper contact is joined tothe upper terminal member by a flexible leader 43. In the form of theinvention shown in Figure 4 the entire reliance for holding the doorclosed is placed upon the latching action of the spring arms I8, whichare formed as described in connection with Figures l and 2.

It will be seen from the disclosure that a novel form of fuse cut-outhas been provided which insures the mechanical separation of at leastone of the contacts of the fuse tube from the corresponding Vstationarycontact of the housing under all conditions, even if the door shouldfreeze tight under, unusual conditions, and that even under theseconditions the fuse tube, which is completely housed, freely slidesdownwardly and provides the mechanical separation of the contactshereinabove referred to when the fuse link hasrbeen severed. Normally,however, the device provides triple safety in opening the electric linethrough the device upon overload, for, in the y rst place, the ruptureof the fuse link with its subsequent quick withdrawal from the fusetube,

either by expulsion action of the fuse tube or through the action of thefuse link extractor, provides a break in the electric circuit which issubsequently followed by the mechanical motion of at least one contactof the fuse tube from the corresponding stationary contact, and thislast is followed also by the motion of the door outwardly anddownwardly, which removes both contacts of the fuse tube from thestationary contacts. It is to be noted particularly that the contacts24, see Figure 3, tend to urge the door outwardly, and that the contact9 tends to urge the fuse tube downwardly, thus providing positive meansfor initiating the motion of these two members.

lt is to be noted that thisl invention provides for an appreciabledownward or vertical travel of the fuse tube whether the door sticksclosed or not. Thus adequate separation at least between the uppercontact of the fuse tube and the corresponding stationary contact of thehousing is assured, thus precluding any possibility of arcing overwithin the housing after the fuse has blown. The downward motionof thefuse tube, therefore, not only releases the door but also provides oneof the multiple safety features of'the device.

It will be seen further that the device may be freely opened and closedwithout placing a strain upon the fuse link, that it will give a visualindication of the fact that the fuse has blown by the position of thedoor under normal conditions, and in the event the door does not openunder abnormal conditions, will still give a visual indication of thefact that the fuse has blown by the projecting of the fuse tube belowthe bottom portion of the device.

It will be seen further that although these 4several functions areobtained by the device, that nevertheless it is very simple inconstruction and may be cheaply made.

It Vwill be seen further that the device may be re-fused with ease andwith safety as the door may be detached from the hook like supports 4,see Figure l, when the door is open. After refusing, the door is rockedclosed and the device is again placed in service. l

Although this invention has been described in considerable dctail, it isto be understood that such description is intended as illustrativerather than limiting, as the invention may be variously embodied and isto be interpreted as claimed.

We claim: l. A\cutout construction comprising a casing, a door movablysupported by said casing and biased towards open position, a tubemovably carried by said door and normally biased to-.

wards movement with respect to said door, latching means holding saiddoor closed and released when said tube moves with respect to said door,said casing and said tube having normally electrically connected contactmeans, said contact means separating when said tube moves from normalposition with reference to said door, a current controlled expulsibleconductor normally holding said tube against motion with respect to saiddoor, said conductor normally completing an electric circuit throughsaid tube and interrupting said circuit within said tube upon overload,and biasing means assisting in the extraction of said conductor.

2. A cut-out construction comprising a casing, a door movably supportedby said casing and biased towards open position, a tube movably carriedby said door and normally biased towards movement with respect to saiddoor, latching means holding said door closed and released when saidtube moves with respect to said door, said casing and said tube havingnormally electrically connected contact means, said contact meansseparating when said tube moves from normal position with reference tosaid door, a current controlled expulsible conductor normally holdingsaid tube against motion with respect to said door, said conductornormally completing anv electric circuit through said tube andinterrupting said circuit within said tube upon overload, and biasingmeans assisting in the extraction of said conductor, said biasing meansinterlocking with said tube and releasing said tube when said expulsibleconductor is expelled.

3. A fuse construction comprising a housing, a door for said housingadapted to move to open position, a fuse tube movable with respect tosaid door from operative to inoperative position and holding said doorclosed when in operative position and releasing said door when ininoperative position, and a fuse link within said tube normally holdingsaid tube against motion with respect to said door and releasing. saidtube when said fuse link is severed, whereby when said fuse link issevered said fuse tube and said door are successively released.

releasing position, a fuse link within said fuse tube restraining saidtube against door-releasing motion, and a fuse link extractor tending towithdraw said fuse link from said fuse tube.

6. A fuse construction comprising a housing, a door biased towards openposition, a fuse tube normally holding said door closed, said fuse tubebeing movable with respect to said door to doorreleasing position andbeing biased towards doorf releasing position, a fuse link withinsaidfuse tube restraining said tube against door-releasing motion, andrecoil resisting means carried jointly by said fuse tube and saidhousing.

7. A fuse construction comprising a housing, a door movably carried bysaid housing and biased towards opening motion, a fuse tube supportedwlthinsaid housing, said fuse tube normally holding said door latched tosaid housing and being movable with respect to said door todoor-releasing position and being biased towards doorreleasing motion,cooperating contact means carried jointly by said housing and fuse tubeand separable' when said fuse tube movesto doorreleasing position, and afuse link within said fuse tube restraining said fuse tube againstdoorreleasing motion.

8. A fuse construction comprising a housing, a door movably carried bysaid housing and biased towards opening motion, a fuse tube carried bysaid door, said fuse tube normally holding said door latched to saidhousing and being movable with respect to said door to door-releasingposition and being biased towards door-releasing motion, cooperatingcontact means carried jointly by said housing and fuse tube andseparable a material distance when said fuse tube moves todoor-releasing position, and a fuse link within said lfuse tuberestraining said fuse tube against door-releasing motion.

9. A fuse construction comprising a housing, a door pivoted with respectto said housing and biased towards open position, a fuse tube carried bysaid door, means cooperating with said fuse tube for normally holdingsaid door latched to said housing, said fuse tube'being movable withrespect to said door to door-releasing position and being biased towardsdoor-releasing position, and a fuse link normally restraining the fusetube against door-releasing movement.

l0. A fuse construction comprising a housing, a door pivoted withrespect to said housing and biased towards open position, a fuse tubecarried by said door, means cooperating with said fuse tube for normallyholding said door latched to said housing, said fuse tube being movablewith respect to said door to door-releasing position and being biasedtowards door-releasing position, contact means located within saidhousing, contact means carried by said fuse tube and normally engagingthe said contact means within said housing and movable a materialdistance from the contact means Within said housing when said fuse tubemoves to door-releasing position, and a fuse link normally restrainingthe fuse tube against door-releasing movement.

11. A fuse construction comprising a housing, a door pivoted adjacentits lower end to said housing, a fuse tube slidably carried by said doorand normally occupying an upper operative position and slidabledownwardly to inoperative position, a pair of stationary contactscarried by said housing, a fuse link carried by said fuse tube andnormally electrically connecting the stationary contacts of saidhousing, lsaid. fuse link preventing downward sliding motion of saidfuse tube and releasing said fuse tube when said fuse link is severed,and latch means carried by said housing and operatively connected tosaid door when said fuse tube is in operative position, said fuse tubeinterruptin'g the operative connection between said latch means and saiddoor when said fuse tube slides downwardly.

12. A fuse construction comprising a housing, a door pivoted adjacentits lower end to said housing, a fuse tube slidably carried by said doorand .normally occupying an upper operative position and slidabledownwardly to inoperative position,

a, pair of stationary contacts carried by said housing, a fuse linkcarried by said fuse tube and normally electrically connecting thestationary contacts of said housing, said fuse link preventing downwardsliding motion of said fuse tube and releasing said fuse tube when saidfuse link is severed, and latch means carried by said housing andnormally interlocking with said fuse tube when said fuse tube is inoperative position, said fuse tube disengaging itself from said latchmeans when said fuse tube moves downwardly to inoperative position uponrupture of said fuse link.

13. A fuse construction comprising a housing, a door pivoted adjacentits lower end to said housing, a fuse tube slidably carried by said doorand normally occupying an upper operative position and slidabledownwardly to inoperative position, a pair of stationary contactscarried by said housing, a fuse link carried by said fuse tube andnormally electrically connecting the stationary contacts of saidhousing, said fuse link preventing downward slidi.\g motion of said fusetube and releasing said fuse tube when said fuse link is severed, and apair of spring arms carried by said housing and between which said fusetube passes when said door is closed and said fuse link is intact, saidspring arms being laterally expanded when said fuse tube passestherebetween, said fuse tube sliding downwardly a material distance fromsaid spring arms and releasing said door when said fuse link is severed.

14. In a fuse construction, a fuse tube, a metal ferrule surrounding aportion of said fuse tube, said ferrule and said fuse tube having atransverse slot cut therein, and a pin located within said slot andlocking said ferrule to said fuse tube, said ferrule having a partthereof extending over said pin to hold said pin.

15. In a fuse construction, a fuse tube, a metal ferrule surrounding aportion of said fuse tube, said ferrule and said fuse tube having atransverse slot cut therein, and a pin located within said slot andlocking said ferrule to said fuse tube, said vferrule having a partthereof extending over said pin to hold said pin and said pin havinginturned ends to prevent displacement of said pin transversely of saidfuse tube.

16. In a cut-out construction, a cut-out member comprising an elongatedinsulating body por tion, a metal ferrule surrounding a part of saidbody portion, said ferrule and said body portion having a transverseslot, a pin located within said slot and locking said ferrule to saidbody portion, said ferrule having slots therein on pposite sides of saidfirst mentioned slot forming transverse bars integral with saidferrule,` said bars extending towards each other over said pin to holdsaid pin in place.

1'7. In a cut-out construction, a cut-out member comprising an elongatedinsulating body portion, a metal ferrule surrounding a part of said bodyportion, said ferrule and said body portion having a transverse slot, apin located within said slot and locking said ferrule to said bodyportion, said ferrule having slots thereinv on opposite sides of saidfirst mentioned slot forming transverse bars integral with s aidferrule, said bars extending towards each other over said pin to holdsaid pin in place, said pin having inturned ends directed towards saidbody portion toprevent displacement of said pin transversely of saidbody portion.

18. A fuse construction comprising a housing having stationary contacts,a door for said housing biased towards open position, a fuse tube withinsaid housing normally holding said door closed, said fuse tube beingmovable with respect to said door to door-releasing position and beingbiased towards door-releasing position, said fuse tube having contactsnormally engaging said f stationary contacts, at least one contact ofsaid fuse tube moving away from the corresponding stationary contact amaterial distance upon blowing of the fuse, and a fuse link within saidfuse tube restraining said fuse tube against doorreleasing motion andelectrically connecting the contacts of said fuse tube.

fuse tube moving downwardly away from the corresponding stationarycontact a material distance upon blowing of the fuse, and a fuse linkwithin said fuse tube restraining said fuse tube against door-releasingmotion and electrically connecting the contacts of said fuse tube.

20. A fuse construction comprising a housing having stationary contacts,a door for said housing biased towards open position, a fuse tube withinsaid housing normally holding said door closed, said fuse tube lbeingmovable with respect to said door to door-releasing position and beingbiased towards door-releasing position, said fuse tube having contactsnormally engaging said stationary contacts, at least one Contact of saidfuse tube moving away from the corresponding stationary contact amaterial distance upon -blowing of the fuse, a fuse link within saidfuse tube restraining said fuse tube against door-releasing motion andelectrically connecting the contacts of said fuse tube, and a fuse linkextractor tending to withdraw said fuse link from said fuse tube.

21. A fuse con-struction comprising a housing having stationarycontacts, a door for said housing, a fuse tube carried by said door andnormally holding said door closed, said fuse tube having contactsnormally electrically connecting said stationary contacts and said fusetube being movable with respect to said door to door-releasing positionand being biased towards door-releasing motion, and a fuse linkelectrically connecting the contacts of said fuse tube and restrainingsaid fuse tube against door-releasing motion, said fuse tube having amaterial substantially vertical motion upon rupture of the fuse link,`whereby a contact of said fuse tube is separated a material distancefrom the corresponding stationary ecntact of said housing upon ruptureof the fuse link, `sfaid door and said fuse tube thereafter rockingoutwardly away from said housing.

22. In a drop-out fuse dev-ice, in combination,l

a sleeve, means for rotatably mounting said sleeve, a fuse tube slidablymounted at one end in said sleeve, a spring biasing said tube formovement relative to said sleeve, a fuse link in said tube tensioned bysaid spring and restraining said tube from movement in said sleeve, aterminal carried by the other end of said tube, a stationary terminaladjacent said other end of said tube, and contact means electricallyinterconnecting said terminals and arranged and adapted to maintainsubstantially constant contact pressure with one of them while said tubemoves through said sleeve after said fuse link blows.

WILLIAM 0. SCHULTZ. ALWIN G. STEINMAYER,

